Floor hinge

A floor hinge embedded in a floor of a building under a door, and comprising a cam (60) coupled to a hinge shaft (10) in a rectangular box-shaped casing, the floor hinge comprising:

• upper and lower plates (20 and 30) fitted over the hinge shaft (10) projecting from the casing (100) to be moved in a lengthwise direction of the upper and lower plates by an operation of the cam (60);
• and
• a support unit (40) having a bent plate shape, and comprising a plate support part (48) and a rod support part (46),
• wherein the plate support part (48) is fastened to a lower surface of a front end of the lower plate (30) using a bolt (32), and the rod support part (46) having on both sides thereof screw holes (42) projects to an outside of the lower plate (30) so that a pair of piston rods (51) extending from a pair of shock absorbers (50) is screwed to the corresponding screw holes (42) and a rear portion of each of the shock absorbers (50) is supported by the casing, so that, when the door is opened, the hinge shaft (10) rotates the cam (60), and each of the piston rods moves in conjunction with the cam, thus compressing each of the shock absorbers, and the piston rods are restored to original states thereof by a restoring force of each of the shock absorbers, thus rotating the hinge shaft in a reverse direction, thereby closing the door.